JP2013226674A - Position detection apparatus of mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detection apparatus of a contact-type mold, capable of reliably preventing damage by a shock, and preventing false detection due to the heat of a die so that a relative position of a fixed die and a movable die can be accurately detected.SOLUTION: A position detection apparatus includes: a detection element 26 that is supported slidably on a support 24 by a guide means 25; and a detection means 27 that detects a position of the detection element 26 that has been subject to displacement control by a contact element 30. One of the support 24 and the detection element 30 is arranged in one of dies that comprise the mold 1. The other of the support 24 and the contact element 30 is arranged in the die that relatively moves with respect to the die in which one of them is arranged so that both of them are opposed to, each other. The displacement of the detection element 26 that is directly displaced by the contact element 30 is detected by the detection means 27 while the relative position of a movable die 4 with respect to a fixed die 3 is displaced so that a relative position of the fixed die 3 and the movable die 4 is detected.

Description

  The present invention relates to a position detection device that detects a relative position between a fixed mold and a movable mold in a molding machine. The position detection device according to the present invention can be applied to an injection molding machine or a die casting machine.

  As an injection molding method, an injection compression molding method in which a movable mold is moved to a fixed mold side after resin filling and molding is performed, or an injection press molding method is known. In the injection compression molding method, as in the normal injection molding method, the molten resin is injected into the cavity in a state where the movable mold is advanced to the mold clamping position by the mold clamping device. At this time, molding is performed by moving the movable mold retreated by the pressure of the injected molten resin again to the mold clamping position by the mold clamping device. In the injection press molding method, a movable mold is advanced to a position just before the mold clamping position by a mold clamping device, and a required amount of molten resin is injected into the cavity while the cavity volume remains slightly large. Thereafter, the movable mold is moved forward to the mold clamping position by the mold clamping device to perform molding. The injection compression molding method is used when molding a relatively large product, and the injection press molding method is used when molding a relatively small product.

  When molding by the above molding method, the precision of the molded product can be improved by accurately controlling the relative position between the fixed mold and the movable mold. It is known in Patent Documents 1 to 4 that the relative position is detected by a position detection device. The position detection device (type position sensor) according to Patent Document 1 includes a distance measuring sensor including an ultrasonic sensor attached to the outer surface of a movable platen, and a detected plate portion attached to the outer surface of the fixed platen. At the time of distance measurement, the relative position between the fixed platen and the movable platen can be detected in a non-contact state by detecting the position of the plate portion to be detected by the distance measuring sensor.

  The position detection device (stroke sensor) of Patent Document 2 is composed of a detection head attached to a fixed platen and a scale attached to a movable platen, and is fixed by reading the number of engraved pitches of the scale with the detection head. The relative position between the board and the movable board is detected. In Patent Document 3, the movement of the movable platen is detected by a position detection device (linear encoder) attached to the movable platen, and the relative position between the fixed platen and the movable platen is detected.

  The position detection device (linear scale) of Patent Document 4 is composed of a detector attached to a moving mold and a scale body attached to a fixed mold, and movement of the moving mold is performed between the detector and the scale body. Measure the amount directly. According to this, as can be seen in the position detection devices of Patent Documents 2 and 3, it is possible to perform measurement with higher accuracy than when a linear scale is attached between the movable platen and the fixed platen.

JP 2010-1111005 (paragraph number 0023, FIG. 1) Japanese Patent Laid-Open No. 06-126801 (paragraph number 0009, FIG. 1) JP 2000-185344 A (paragraph numbers 0017, 0018, FIG. 1) JP 2006-289860 A (paragraph number 0046, FIG. 1)

  In an injection molding machine or a die-cast molding machine, molding is performed with a molding die heated in order to improve the fluidity of plastic or metal during molding. For this reason, in the case of the position detection device of Patent Document 1 that detects the relative position of both molds with an ultrasonic sensor, the air between the ultrasonic sensor and the plate portion to be detected is heated by the heat of the mold, Temperature unevenness occurs in the air in the distance measuring part. As a result, the sound speed of the distance measurement portion is not constant, and it is inevitable that an error occurs in the distance measurement accuracy by the ultrasonic sensor. Also, in the case of a distance measuring sensor using a laser as a distance measuring element, there is a possibility that an error occurs due to a change in the refractive state of the laser due to air temperature unevenness. Further, when a laser is used as a distance measuring element, it is easily affected by the surface roughness or contamination of the plate portion to be detected, and it takes a lot of time to maintain the surface state of the plate portion to be detected in a suitable state. .

  In the position detection devices of Patent Documents 2 and 3, since the movement amount of the scale or the movable platen is detected by the stroke sensor or the linear encoder, there is no room for the error due to the air temperature unevenness as described above. However, the sensor element is fixed to the stationary platen and the movable platen that support the mold, and the relative position between the stationary platen and the movable platen is indirectly detected as the relative position between the stationary die and the movable die. An error is likely to occur in the detected value due to the mounting state of the mold or the thermal expansion of the mold. As a result, the finished dimensions of the molded product are likely to vary. In addition, there is a disadvantage that the molding machine is increased in size by the space for mounting the sensor element.

  In the position detection device of Patent Document 4, since the detector and the scale body constituting the linear scale are directly attached to the moving mold and the fixed mold, respectively, it is possible to prevent the occurrence of errors as in Patent Documents 2 and 3. it can. However, since the detector and the scale main body are thermally expanded by the heat of the mold, it is inevitable that the measurement accuracy is lowered. Further, the attachment portion between the detector and the scale main body and each mold is thermally expanded and the relative positional relationship is shifted, so that they may come into contact with each other and be damaged.

  In addition to the position detection devices of Patent Documents 1 to 4, non-contact sensors such as an eddy current clearance sensor or a magnet scale sensor are used as sensors for detecting the relative position between the fixed mold and the movable mold in the vicinity of the mold clamping position. Has been used in the past. These non-contact sensors are fixed to either a fixed mold or a movable mold, and the other mold is detected by the sensor to detect the relative position of both molds. However, the eddy current type clearance sensor and the magnet type scale sensor have a large influence on the detection value due to the structure and material of the mold to be mounted, or the magnetic characteristics of the mold surface, and the sensor and mold must be maintained frequently. There is.

  By the way, in a molding machine that molds large products, in order to shorten the molding cycle, the forward movement for mold clamping is performed at high speed until just before the mold clamping position, and then the mold is decelerated and clamped. . For this reason, in a contact sensor in which the detector is brought into direct contact with the mold, the impact applied to the detector is increased and the sensor is easily damaged. Further, at the moment when the detector contacts the mold, the detector is repelled and a bounce phenomenon occurs, and the detection value of the sensor is disturbed as shown in FIG. Specifically, a plurality of points having the same relative position of both molds on different time axes are detected. For this reason, the control unit of the molding machine determines that there is an abnormality in the sensor and causes an emergency stop of the molding machine. For these reasons, non-contact sensors are frequently used even when frequent maintenance is required. Then, as a result of studying to solve the problems of the contact sensor, the present inventors have proposed the present invention.

An object of the present invention is a contact type that can reliably prevent damage due to impact, or prevent erroneous detection due to heat of the mold, and can accurately detect the relative position between the fixed mold and the movable mold near the mold clamping position. An object of the present invention is to provide a position detecting device for a molding die.
An object of the present invention is to provide a contact-type mold detection device that can reliably detect the relative position between a fixed mold and a movable mold by reliably preventing the detector from falling into a bounce phenomenon. There is to do.

  The molding die position detecting device according to the present invention detects the relative position between the stationary die 3 and the movable die 4. The position detection device 2 includes a support 24, a detector 26 that is supported by the support 24 so as to be slidable back and forth by guide means 25, a contact 30 that operates to displace the detector 26 during mold clamping, and a support 24. And a detecting means 27 that detects the position of the detector 26 that is provided and displaced by the contact 30. The guide means 25 includes guide bodies 37 and 77 fixed to the support body 24 and slide bodies 38 and 78 that are slidably supported by the guide bodies 37 and 77. Either one of the support 24 and the contact 30 is arranged in any one of the molds constituting the molding die 1, and the other of the support 24 and the contact 30 is connected to the support 24 and the contact 30. And the detector 26 and the contact 30 are made to face each other. In a state where the relative position of the movable mold 4 is displaced with respect to the fixed mold 3, the detector 26 is directly displaced by the contact 30, and the displacement of the detector 26 is detected by the detection means 27, and the fixed mold 3 is detected. The relative position of the movable mold 4 is detected.

  The molding die 1 according to the present invention includes a fixed die 3 and a movable die 4, and a fixed die 3 and a movable die as shown in FIGS. 2 and 11. There are cases where the mold 4 and the frame-shaped mold 5 assembled to the movable mold 4 are composed of three molds. Furthermore, it may be configured with three or more molds. In such a molding die 1, “any one of the support 24 and the contact 30 is arranged in any one of the molds constituting the molding die 1” means the support 24 (or the contact 30). Means that it is arranged in any one of the fixed mold 3, the movable mold 4, and the frame-shaped mold 5. Further, “the other side of the support 24 and the contact 30 is placed in a mold that moves relative to the mold in which one of the support 24 and the contact 30 is arranged” means that the contact 30 (Or support 24) means that it is arranged in a mold that moves relative to the previous mold.

  The detecting means 27 is constituted by a linear sensor provided with a sensor rod 28 that moves along with the detector 26 and a sensor head 29 that is fixed to the support 24 and detects the position of the sensor rod 28. The detector 26 is urged by the return springs 49 and 92 toward the standby position protruding from the support 24 toward the contact 30.

  A damping mechanism 56 is provided between the support 24 and the slide body 38 to apply a damping force to the slide body 38 when the detector 26 is displaced. The abrupt movement of the detector 26 when the detector 26 is displaced by the contact 30 is restricted by the attenuation mechanism 56.

  The damping mechanism 56 includes a damper chamber 54 formed in the support 24 so as to surround the slide body 38, and a liquid oil 55 sealed in the damper chamber 54. In a state in which the detector 26 is displaced by the contact 30, the sudden movement of the detector 26 is restricted by the shearing force generated between the slide body 38 and the liquid oil 55.

  A liquid holder 63 impregnated with liquid oil 55 is disposed in the damper chamber 54, and the liquid holder 63 is externally attached to the slide body 38.

  The liquid holder 63 includes a ring-shaped felt 65 and a shape-retaining member 64 that is attached to the outer surface of the felt 65 and holds the shape of the felt 65.

  A communication hole 59 through which liquid oil and fat 55 is put into and out of the damper chamber 54 is formed in the support 24, and the communication hole 59 is closed with a removable plug body 62. In a state where the plug body 62 is removed from the support 24, the liquid oil / fat 55 can be supplied into the damper chamber 54 or the liquid oil / fat 55 in the damper chamber 54 can be replaced.

  A form in which the liquid oil 55 is silicone oil can be taken.

  In the molding die position detecting device of the present invention, the guide body 25 that slidably supports the detector 26 on the support body 24 is constituted by the guide bodies 37 and 77 and the slide bodies 38 and 78. According to this, even when a large impact is applied to the detector 26 during mold clamping, the detector 26 can be slid and guided while being firmly supported, so that the detector 26 can be reliably damaged. Can be prevented.

  In addition, any one of the support 24 and the contact 30 is disposed in any one mold constituting the molding die 1, and either one of the support 24 and the contact 30 is disposed. The other side of the support 24 and the contact 30 is arranged on a mold that moves relative to the mold so that the detector 26 and the contact 30 are opposed to each other. In a state where the relative position of the movable mold 4 is displaced with respect to the fixed mold 3, the detector 26 is directly displaced by the contact 30, and the displacement of the detector 26 is detected by the detection means 27, and the fixed mold 3 is detected. The relative position of the movable mold 4 was detected.

  According to the position detection device as described above, it is possible to eliminate an error that occurs when the sensor element is attached to the movable platen and the fixed platen, and the relative position between the fixed die 3 and the movable die 4 can be accurately determined. Can be detected. In addition, the detection value is not affected by the structure and material of the mold to be mounted, or the magnetic characteristics of the mold surface. Further, the detected value is not affected by the temperature unevenness of the surrounding air due to the heat of the mold.

  The detecting means 27 is composed of a linear sensor including a sensor rod 28 that moves along with the detector 26 and a sensor head 29 that is fixed to the support 24 and detects the position of the sensor rod 28. According to this, since the linear sensor 27 can detect the displacement amount with high resolution, the relative position between the fixed mold 3 and the movable mold 4 can be accurately detected. The accuracy of the molded product to be produced can be improved. Further, since the detector 26 is urged by the return spring 49 toward the standby position that protrudes from the support 24 toward the contact 30, the detector 26 is always held within the movable range of the detector 26. The relative position between the fixed mold 3 and the movable mold 4 can be accurately detected.

  A damping mechanism 56 is provided between the support 24 and the slide body 38 to apply a damping force to the slide body 38 when the detector 26 is displaced, and the detector 26 is displaced by the contact 30. The abrupt movement of the detector 26 is regulated by the damping mechanism 56. According to this, the bounce phenomenon that occurs when the contact 30 and the detector 26 come into contact with each other can be prevented. Specifically, in the state immediately before the movable mold 4 is decelerated, the bounce phenomenon occurs when the contactor 30 and the detector 26 come into contact with each other. Is caused by sudden movement at a speed higher than the mold clamping speed. However, if the sudden movement of the detector 26 is restricted by the attenuation mechanism 56, the detector 26 is prevented from being repelled and the detector 26 is synchronized with the movement of the contact 30 as shown in FIG. It can be moved smoothly. Therefore, even if the mold clamping speed is high, the bounce phenomenon does not occur, and the relative position between the fixed mold 3 and the movable mold 4 can be accurately detected.

  When the damping mechanism 56 is configured by using the slide body 38 and the liquid oil 55 sealed in the damper chamber 54 as a damping element, the abrupt force of the slide body 38 is caused by the damping force derived from the shearing force generated between the both damping elements. The movement can be precisely regulated. Therefore, the structure of the attenuation mechanism 56 can be simplified and the manufacturing cost of the position detection device 2 can be suppressed. Moreover, since the shearing force generated according to the difference in viscosity of the liquid oil 55 used can be adjusted, the damping force acting on the slide body 38 can be changed simply by replacing the liquid oil 55 used. There is also an advantage that can be done.

  After the initial displacement of the detector 26, the liquid oil 55 tries to convect in the damper chamber 54 by being pulled by the slide body 38. When convection of the liquid oil / fat 55 occurs, the generated shearing force is reduced and a sufficient damping force cannot be applied to the slide body 38. However, when the liquid holding body 63 impregnated with the liquid oil 55 is disposed in the damper chamber 54, the liquid holding body 63 can suppress the occurrence of convection of the liquid oil 55, so that a constant damping force is applied to the slide body 38. Can do.

  When the liquid holding body 63 is formed of the felt 65, the felt 65 is a material formed by entanglement of fibers, and thus has high liquid absorption and is flexible, so that the liquid oil 55 can be impregnated with certainty. Therefore, when the felt 65 and the slide body 38 slide relative to each other, the slide body 38 is not damaged and the liquid oil 55 in the damper chamber 54 can be prevented from leaking through the damage.

  When the liquid holding body 63 is configured by the ring-shaped felt 65 and the shape retaining member 64 that is attached to the outer surface of the felt 65 and retains the felt shape, the shape retaining member 64 can reliably maintain the shape of the felt 65. And the occurrence of convection of the liquid oil 55 can be reliably suppressed. Further, by adding the shape-retaining member 64, it is possible to prevent the fibers from falling off, so that it is possible to prevent the waste fibers from floating in the liquid oil 55.

  When the communication hole 59 formed in the support body 24 is closed with the removable plug body 62, the liquid oil 55 is replenished in the damper chamber 54 by removing the plug body 62 from the support body 24, or in the damper chamber 54. The liquid oil 55 can be exchanged. Therefore, the replenishment or replacement of the liquid oil / fat 55 can be easily performed without disassembling the support 24, and the maintainability of the position detection device 2 can be improved.

  If the liquid oil 55 is silicone oil, the silicone oil has little change in viscosity due to temperature, so that the change in shearing force due to the temperature of the silicone oil can be suppressed, and a position detection device around the mold that becomes high temperature. Even when 2 is arranged, an appropriate shearing force can be generated. In addition, silicone oil has extremely high resistance to shearing, and shear deterioration at high speed and high load hardly occurs, so that an appropriate shearing force can be generated over a long period of time.

It is a front view which shows the principal part of the position detection apparatus which concerns on 1st Example of this invention. It is a front view of a molding machine. It is a vertical front view of a position detection device. It is a disassembled perspective view of a support body. It is a disassembled perspective view of a position detection apparatus. It is the sectional view on the AA line in FIG. It is an expanded sectional view showing operation of a damping mechanism. It is a graph which shows the detected value of the position detection apparatus of this invention. It is a graph which shows the detected value of a position detection apparatus when a bound phenomenon generate | occur | produces. It is a cross-sectional top view of the position detection apparatus which concerns on 2nd Example of this invention. It is a front view of a molding machine. It is a disassembled perspective view of a position detection apparatus. It is the BB sectional drawing in FIG.

First Embodiment FIGS. 1 to 8 show a first embodiment in which a molding die position detecting device according to the present invention is applied to a plastic injection molding machine using an injection compression molding method. In the present invention, front / rear, left / right, and upper / lower follow the cross arrows shown in the figure and the front / rear, left / right, and upper / lower indications shown near each arrow. FIG. 2 shows the configuration of an injection molding machine. Reference numeral 1 is a molding die, 2 is a position detection device, 7 is an injection device, 8 is a clamping device, and 9 is a control unit that controls the injection molding machine. .

  As shown in FIG. 2, the injection device 7 includes a heating barrel 10, a screw 11 disposed in the heating barrel 10, a hopper 12 into which a chip-shaped resin as a raw material is charged. The injection device 7 is configured to be movable in the front-rear direction by a linear drive mechanism (not shown). The screw 11 is configured to be rotationally driven and movable in the front-rear direction by a drive mechanism (not shown). The chip-shaped resin charged into the hopper 12 is conveyed while being heated and compressed in the heating barrel 10 by the screw 11 and is injected in a molten state from a nozzle 13 formed at the tip of the heating barrel 10. The molten resin is injected in a state where the injection device 7 is moved and the nozzle 13 is connected to the gate of the molding die 1.

  As shown in FIG. 2, the mold clamping device 8 includes a fixed platen 15, a movable platen 16, a support plate 17, a tie bar 18, a toggle type mold clamping mechanism 19, and the like. The mold clamping mechanism 19 includes a toggle mechanism 20 that connects the movable platen 16 and the support plate 17, a motor 21 that moves the toggle mechanism 20 close or away, a feed screw 22, and the like. The fixed platen 15 and the support platen 17 are integrally formed via a tie bar 18, and the movable platen 16 is guided by the tie bar 18 so as to be close to or away from the fixed platen 15. Yes. The molding die 1 is attached to the fixed platen 15 and the movable platen 16.

  As shown in FIG. 2, the molding die 1 is composed of a stationary die 3, a movable die 4, and a frame-like die 5 that is integrally provided in a state that can slide relative to the movable die 4. It is. The frame-shaped mold 5 is a spring provided between the movable mold 4 and the frame-shaped mold 5 and is urged forward toward the fixed mold 3. When the molding mold 1 is opened, The front surface of the middle part of the movable mold 4 and the rear surface of the frame-shaped mold 5 are separated from each other. When the mold 1 is clamped by the mold clamping mechanism 19, the rear surface of the fixed mold 3 and the front surface of the frame-shaped mold 5, and the rear surface of the frame-shaped mold 5 and the front surface of the middle portion of the movable mold 4 Are in close contact with each other, and a cavity is formed between the fixed mold 3 and the movable mold 4. The mold clamping position of the movable mold 4 is detected by a mold clamping position detection sensor (not shown), and the control unit 9 controls the motor 21 so that the movable mold 4 is located at the mold clamping position. To control.

  A gate is formed in the fixed mold 3, and molten resin is injected into the cavity via the gate by the injection device 7. When the injection compression molding method is used with the molding die 1 provided with the frame-shaped mold 5, when the molten resin is injected into the cavity, the movable mold 4 and the frame-shaped mold 5 are caused by the pressure of the molten resin. Retreating in close contact, the relative position with the fixed mold 3 is separated. At this time, the control unit 9 controls the motor 21 so that the movable mold 4 and the frame-shaped mold 5 are not separated from the fixed mold 3 more than necessary. In order to detect the relative position between the fixed mold 3 and the movable mold 4 during the control, a position detection device 2 is provided in the molding mold 1.

  As shown in FIGS. 1 to 3, the position detection device 2 includes a support 24, a detector 26 supported by the support 24 so as to be slidable back and forth by a guide means 25, and a displacement operation of the detector 26 during mold clamping. And a linear sensor (detection means) 27 that detects the position of the detector 26 that is provided on the support 24 and is displaced by the contactor 30. The support 24 is disposed in the fixed mold 3. The linear sensor 27 includes a sensor rod 28 that is displaced integrally with the detector 26, and a cylindrical sensor head 29 that is fixed to the support 24 and detects the position of the sensor rod 28. The sensor head 29 is fixed to the support 24 in a state where the sensor rod 28 is inserted into the cylinder.

  A coil group consisting of a primary coil and a plurality of secondary coils is provided on the inner peripheral surface of the cylindrical sensor head 29 of the linear sensor 27, and the sensor rod 28 includes a plurality of magnetic response members. Has been inserted. When an AC signal is applied to the primary coil, an electrical signal corresponding to the amount of displacement of the sensor rod 28 in the front-rear direction with respect to the coil group is output from the secondary coil.

  As shown in FIGS. 2 and 3, a contact 30 for displacing the detector 26 is fixed to the frame-shaped mold 5 with a cap bolt. The contact 30 is formed by bending a plate body into an L-shaped cross section, and is reinforced by welding three reinforcing ribs 31. When the contact 30 displaces the detector 26 together with the sensor rod 28, the sensor head 29 outputs an electrical signal corresponding to the amount of displacement of the sensor rod 28 to the control unit 9, and the control unit 9 outputs the electrical signal as position information. Process and control the injection molding machine. As described above, since the movable mold 4 and the frame-shaped mold 5 are moved back in close contact with each other by the pressure of the molten resin, the support 24 and the contact are placed on the fixed mold 3 and the frame-shaped mold 5. By fixing 30, the relative position between the fixed mold 3 and the movable mold 4 can be detected by the position detection device 2.

  As shown in FIGS. 3, 5, and 6, the detector 26 includes a detector base 33 and a contact plate 34 that is fixed to the rear surface side of the detector base 33 and contacts the contact 30. The contact plate 34 is fastened and fixed to the detector base 33 with a cap bolt. On the front side of the detector base 33, the sensor rod 28 is fixed in a state where its axis is orthogonal to the detector base 33. Specifically, the sensor rod 28 is fixed to the detector base 33 in a state where the rear end of the sensor rod 28 is held between the fixed plates 35. Since the contact plate 34 that contacts the contact 30 is fastened and fixed to the detector base 33, if the contact plate 34 needs to be replaced due to wear or the like, the contact plate 34 can be easily replaced. .

  As shown in FIGS. 3 and 5, the support 24 is provided with two sets of guide means 25 with the sensor rod 28 interposed therebetween. The guide means 25 includes a linear bush (guide body) 37 and a slide rod (slide body) 38 slidably supported by the linear bush 37. The slide rod 38 and the sensor rod 28 described above are arranged so that the axial directions of both are parallel. On the rear end side of the slide rod 38, the detector base 33 of the detector 26 is fastened and fixed with a cap bolt screwed into the slide rod 38. A connecting plate 39 is fastened and fixed to the front end side of the pair of slide rods 38 by cap bolts screwed into the slide rods 38, and the front end of the sensor rod 28 is inserted into an insertion hole formed in the central portion of the connecting plate 39. Has been. As a result, the sensor rod 28 is supported in a supported state by the detector base 33, the connecting plate 39, and the two slide rods 38 connecting the two. Two locking pins 40 for locking a return spring 49 described later are provided on the upper and lower surfaces of the connecting plate 39, respectively. In FIG. 3, reference numeral 41 denotes a stopper pin fixed to the surface of the detector base 33 facing the support 24 and the surface of the support 24 facing the connecting plate 39, and the pin 41 is the support. 24 and the connection plate 39 are in contact with each other to define the movement limit of the front and rear of the slide stroke of the detector 26.

  As shown in FIGS. 4 and 6, the support body 24 includes a support block 43 and a block cover 44 fixed to the rear surface side of the support block 43. The support body 24 is fastened and fixed to a mounting base 45 (see FIG. 6) provided in the fixed mold 3 with a cap bolt, whereby the support body 24 is fixed to the fixed mold 3. As shown in FIG. 4, mounting holes 46 for mounting the linear bush 37 are formed on the upper and lower sides of the support block 43 so as to penetrate forward and backward, and the sensor head 29 is fixed between the mounting holes 46 and 46. A fixing hole 47 is formed so as to penetrate forward and backward. Two locking pins 48 are provided on the upper and lower surfaces of the support block 43 to lock a return spring 49 described later.

  As shown in FIG. 3 and FIG. 5, the return spring 49 is formed of a tension coil type spring, and is detected by being locked to the locking pin 40 of the connecting plate 39 and the locking pin 48 of the support block 43. The child 26 is urged toward the standby position (rear end position). Accordingly, the detector 26 is located at the rear end position in a state where it is not in contact with the contact 30, and is displaced in the front-rear direction following the contact 30 in a state where it is in contact with the contact 30.

  The block cover 44 is joined to the rear surface of the support block 43 and fastened and fixed with a cap bolt. On the upper and lower sides of the block cover 44, corresponding to the mounting holes 46 opened in the support block 43, insertion holes 51 for inserting the slide rod 38 are formed in a state of penetrating in the front-rear direction. Further, an insertion hole 52 for inserting the sensor rod 28 is formed between the upper and lower insertion holes 51 and 51 so as to pass through in the front-rear direction. As shown in FIG. 3, the support 24 is covered with a cover 66 while being fixed to the mounting base 45.

  As shown in FIG. 1, the insertion hole 51 is formed in a stepped hole shape with a large-diameter hole on the front surface side and a small-diameter hole on the rear surface side. An oil seal 53 is provided on the inner peripheral surface of the small-diameter hole, and the large-diameter hole portion and a part of the small-diameter hole portion between the oil seal 53 and the packing 58 attached to the rear surface of the linear bush 37 are provided. A damper chamber 54 is formed. The damper chamber 54 is filled with liquid oil 55, and the damper chamber 54 and the liquid oil 55 constitute an attenuation mechanism 56.

  When the detector 26 is displaced, the damping mechanism 56 suppresses a sudden movement of the slide rod 38 by a shearing force generated between the slide rod 38 and the liquid oil 55, and the detector 26 falls into a bound phenomenon. prevent. The liquid oil 55 is preferably silicone oil. This is because silicone oil has a small change in viscosity with temperature, that is, a change in shearing force, and can generate a shearing force appropriately even around a mold at a high temperature. In addition, the silicone oil 55 has extremely high resistance to shearing, hardly undergoes shearing deterioration at a high speed and a high load, and can exhibit an appropriate shearing force over a long period of time.

  As shown in FIG. 1, an O-ring 57 for preventing leakage of the liquid oil 55 is disposed between the block cover 44 and the linear bush 37, and similarly, between the slide rod 38 and the linear bush 37. Is provided with a packing 58. A communication hole 59 communicating with the damper chamber 54 is formed on the rear surface of the block cover 44. The communication hole 59 in a normal state is closed with a screw 61 screwed into the hole 59, and an O-ring attached to the screw 61. Sealed at 60. The screw 61 and the O-ring 60 constitute a plug body 62.

  As shown in FIG. 1, a liquid holder 63 that fits around the slide rod 38 is disposed in the damper chamber 54. The liquid holder 63 is attached to the ring-shaped felt 65 and the outer surface of the felt 65. And a shape-retaining member 64. The shape-retaining member 64 is attached to hold the shape of the ring-shaped felt 65. The thickness dimension in the front-rear direction combining the felt 65 and the shape retaining member 64 is set to be smaller than the depth dimension in the front-rear direction of the large-diameter hole portion of the insertion hole 51, and when the slide rod 38 slides back and forth, The liquid holder 63 can move slightly back and forth.

  When the detector 26 is in the standby position (the state shown in FIG. 3), the liquid holder 63 is received by the bottom wall of the large-diameter hole portion of the damper chamber 54 as shown in FIG. Yes. From this state, at the time of mold clamping in which the detector 26 is displaced forward by the contact 30, a shearing force is generated at the boundary surface between the slide rod 38 and the liquid oil 55. This shearing force becomes a damping force that suppresses the sliding movement of the slide rod 38, and restricts the sudden movement of the detector 26. In addition, at the initial stage of sliding of the slide rod 38, as shown in FIG. 7B, the liquid holding body 63 moves forward while accompanying the slide rod 38 and contacts the linear bush 37. In the meantime, the resistance force when the liquid holding body 63 pushes away the liquid oil 55 between the liquid holding body 63 and the linear bush 37 acts on the slide rod 38 as a damping force. Thereby, a larger damping force can be applied to the slide rod 38 at the initial stage of the slide where the bounce phenomenon is likely to occur. The damping force at this time is sufficiently larger than the damping force after the liquid holding body 63 contacts the linear bush 37. In addition, since the convection of the liquid oil 55 in the damper chamber 54 can be suppressed by the liquid holding body 63, a certain damping force can be applied to the slide rod 38.

  After the initial displacement of the detector 26, the liquid oil 55 tries to convect in the damper chamber 54 by being pulled by the slide body 38. When convection of the liquid oil / fat 55 occurs, the generated shearing force is reduced and a sufficient damping force cannot be applied to the slide body 38. However, when the liquid holding body 63 impregnated with the liquid oil 55 is disposed in the damper chamber 54, the liquid holding body 63 can suppress the occurrence of convection of the liquid oil 55, so that a constant damping force is applied to the slide body 38. Can do.

  When the operating force of the detector 26 by the contact 30 is released, the detector 26 receives the urging force of the return spring 49 and moves backward, and the liquid holder 63 moves backward while accompanying the slide rod 38. The rear surface is received by the bottom wall of the large-diameter hole of the damper chamber 54 and returns to the standby position. Thus, in the state where the detector 26 is returned to the standby position, the liquid holding body 63 is always received by the bottom wall of the large-diameter hole portion of the damper chamber 54.

  As described above, the molding die position detecting device according to the present embodiment is configured so that the linear bush 37 and the slide rod 38 are used to detect the detector 26 even when a large impact is applied to the detector 26 during clamping. Since the guide means 25 is slidably supported, the slide guide can be guided while the detector 26 is firmly supported. Therefore, the detector 26 can be prevented from being damaged, and the relative position between the fixed mold 3 and the movable mold 4 can be reliably detected.

  In addition, the detector 26 and the contact 30 are arranged on the fixed mold 3 and the frame-shaped mold 5, respectively, so that both face each other. In a state where the relative position of the movable mold 4 is displaced with respect to the fixed mold 3, the detector 26 is directly displaced by the contact 30, and the displacement of the detector 26 is detected by the detection means 27, and the fixed mold 3 is detected. The relative position of the movable mold 4 was detected. According to such a position detection device, it is possible to eliminate an error that occurs when the sensor element is attached to the movable platen and the fixed platen, and the relative position between the fixed die 3 and the movable die 4 can be accurately determined. Can be detected. In addition, the detection value is not affected by the structure and material of the mold to be mounted, or the magnetic characteristics of the mold surface. Further, the detected value is not affected by the temperature unevenness of the surrounding air due to the heat of the mold.

  Since the detection means 27 is a high-resolution linear sensor composed of the sensor rod 28 and the sensor head 29, the relative position between the fixed mold 3 and the movable mold 4 can be accurately detected, and the molding mold 1 can improve the dimensional accuracy and shape accuracy of the product molded in step 1. Further, since the detector 26 is urged by the return spring 49 toward the standby position protruding from the support 24 toward the contact 30, the detector 26 can be brought into close contact with the contact 30 and can be followed. The relative position between the mold 3 and the movable mold 4 can be accurately detected.

  Since the attenuating mechanism 56 restricts a sudden movement when the detector 26 is displaced, the bounce phenomenon in which the detector 26 is repelled by the elasticity of both at the moment when the contact 30 and the detector 26 come into contact with each other is wiped out. be able to. Therefore, even if the mold clamping speed is high, it is possible to eliminate the bounce phenomenon and reliably detect the relative position between the fixed mold 3 and the movable mold 4.

  Since the sudden movement of the slide rod 38 is suppressed by the damping force derived from the shearing force generated between the slide rod 38 and the liquid oil 55 sealed in the damper chamber 54, the slide rod 38 can be configured with a simpler configuration. A damping force can be applied. Therefore, the structure of the attenuation mechanism 56 can be simplified and the manufacturing cost of the position detection device 2 can be suppressed. Moreover, since the shear force generated according to the difference in viscosity of the liquid oil 55 used can be adjusted, the damping force acting on the slide rod 38 can be changed simply by replacing the liquid oil 55 used. There is also an advantage that can be done.

  When the liquid holding body 63 impregnated with the liquid oil 55 is disposed in the damper chamber 54, the liquid holding body 63 can suppress the convection of the liquid oil 55 generated after the initial displacement of the detector 26, so that a constant damping force slides. It can act on the body 38.

  When the liquid holding body 63 is configured by the ring-shaped felt 65 and the shape-retaining member 64 that holds the felt shape, the felt 65 is a material formed by entanglement of fibers, and thus has high liquid absorption and is flexible. Therefore, the liquid fat 55 can be surely impregnated. Therefore, when the felt 65 and the slide body 38 slide relative to each other, the slide body 38 is not damaged and the liquid oil 55 in the damper chamber 54 can be prevented from leaking through the damage. Moreover, the shape of the felt 65 can be reliably maintained by the shape-retaining member 64, and the occurrence of convection of the liquid oil 55 can be suppressed. Furthermore, by adding the shape-retaining member 64, it is possible to prevent the fibers from falling off, and thus it is possible to prevent the waste fibers from floating in the liquid oil 55.

  When the communication hole 59 formed in the support 24 is closed by the removable plug body 62, the liquid oil 55 is supplied into the damper chamber 54 or the liquid in the damper chamber 54 is removed by removing the plug body 62 from the support body 24. The replacement of the oil / fat 55 can be easily performed without disassembling the support 24, and the maintainability of the position detection device 2 can be improved.

  In the above embodiment, the molding die 1 is composed of the fixed die 3, the movable die 4, and the frame-like die 5, but this is not necessary, and there are two fixed die 3 and movable die 4. The molding die 1 may be configured. In this case, the position detection device 2 can be used as a mold clamping position detection sensor by detecting the output value of the linear sensor 27 at the mold clamping position in advance.

Second Embodiment FIGS. 10 to 13 show a second embodiment in which the molding die position detecting apparatus according to the present invention is applied to a plastic injection molding machine using an injection press molding method. FIG. 11 shows the configuration of an injection molding machine. Reference numeral 1 is a molding die, reference numeral 2 is a position detection device, reference numeral 7 is an injection device, reference numeral 8 is a clamping device, and reference numeral 9 is a control unit for controlling the injection molding machine. It is. The mold clamping device 8 of the injection molding machine according to this embodiment includes a fixed platen 15, a movable platen 16, a support plate 17, a tie bar 18, a hydraulic cylinder 70, and the like. The point which directly moves 16 is different from the mold clamping apparatus 8 of the first embodiment. Since others are the same as those of the first embodiment, the same members are denoted by the same reference numerals and the description thereof is omitted.

  The hydraulic cylinder 70 is connected to a hydraulic pump (not shown). The fixed platen 15 and the support platen 17 are integrally formed via a tie bar 18, and the movable platen 16 is guided by the tie bar 18 so as to be close to or away from the fixed platen 15. Yes. The molding die 1 is attached between the fixed platen 15 and the movable platen 16.

  As shown in FIG. 11, the molding die 1 is composed of a fixed die 3, a movable die 4, and a frame-like die 5 that is integrally provided so as to be slidable relative to the movable die 4. It is. The frame-shaped mold 5 is a spring provided between the movable mold 4 and the frame-shaped mold 5 and is urged forward toward the fixed mold 3. When the molding mold 1 is opened, The front surface of the middle part of the movable mold 4 and the rear surface of the frame-shaped mold 5 are separated from each other. When the mold 1 is clamped by the hydraulic cylinder 70, the rear surface of the fixed mold 3 and the front surface of the frame-shaped mold 5 and the rear surface of the frame-shaped mold 5 and the front surface of the middle portion of the movable mold 4 are separated. A cavity is formed between the fixed mold 3 and the movable mold 4 in close contact with each other. The mold clamping position of the movable mold 4 is detected by a mold clamping position detection sensor (not shown), and the control unit 9 controls the hydraulic cylinder 70 so that the movable mold 4 is positioned at the mold clamping position. Control to do.

  A gate is formed in the fixed mold 3, and molten resin is injected into the cavity through the gate by the injection device 7. When the injection press molding method is used with the molding die 1 having the frame-shaped die 5, the control unit 9 controls the hydraulic cylinder 70 to inject the movable die 4 before injecting the molten resin into the cavity. Slightly retract from the clamping position. At this time, the frame-shaped mold 5 slides relative to the movable mold 4 while being biased by the spring, so that only the movable mold 4 is slightly retracted. In order to detect the relative position between the fixed mold 3 and the movable mold 4 during the control, a position detection device 2 is provided in the molding mold 1.

  The position detection device 2 includes a support 24, a detector 26 that is supported by the support 24 so as to be slidable back and forth by guide means 25, a contact 30 that operates to displace the detector 26 during mold clamping, and a support 24. A linear sensor (detection means) 27 that detects the position of the detector 26 that is provided and is displaced by the contact 30 is configured. The support 24 is disposed on the movable mold 4. The linear sensor 27 includes a sensor rod 28 that is displaced integrally with the detector 26, and a cylindrical sensor head 29 that is fixed to the support 24 and detects the position of the sensor rod 28. The sensor head 29 is fixed to the support 24 in a state where the sensor rod 28 is inserted into the cylinder.

  A coil group consisting of a primary coil and a plurality of secondary coils is provided on the inner peripheral surface of the cylindrical sensor head 29 of the linear sensor 27, and the sensor rod 28 includes a plurality of magnetic response members. Has been inserted. When an AC signal is applied to the primary coil, an electrical signal corresponding to the amount of displacement of the sensor rod 28 in the front-rear direction with respect to the coil group is output from the secondary coil.

  As shown in FIGS. 10 and 13, a contact 30 for displacing the detector 26 is fixed to the movable mold 4 with a cap bolt. The contact 30 is formed by bending a plate body into an L-shaped cross section, and is reinforced by welding two reinforcing ribs 31. When the contact 30 displaces the detector 26 together with the sensor rod 28, the sensor head 29 outputs an electrical signal corresponding to the amount of displacement of the sensor rod 28 to the control unit 9, and the control unit 9 outputs the electrical signal as position information. Process and control the injection molding machine. As described above, when the movable mold 4 is slightly retracted from the clamping position, only the movable mold 4 is retracted. Therefore, the support 24 and the contact are placed on the movable mold 4 and the frame-shaped mold 5. By fixing 30, the relative position between the fixed mold 3 and the movable mold 4 can be detected by the position detection device 2. As shown in FIG. 11, the position detection device 2 is arranged in a state where the detector 26 and the contact 30 are in contact with each other in a state where the molding die 1 is opened.

  As shown in FIGS. 10, 12, and 13, the detector 26 includes a wedge-shaped detector base 72, a contact body 73 that is fixed to the rear surface side of the detector base 72 and contacts the contact 30, and will be described later. And a fixing plate 74 for fixing the slide block (sliding body) 78 to be fixed. The slide block 78 is fastened by a contact body 73 screwed into the rear end of the slide block 78 in a state of being sandwiched between the detector base 72 and a fixed plate 74 fastened to the base 72. 72 is integrated. Thereby, the detector 26 is fixed to the rear end side of the slide block 78. An insertion hole 75 is formed near the free end of the detector base 72, and the two sensor bolts are screwed in with the rear end of the sensor rod 28 inserted into the insertion hole 75. It is fixed to the detector base 72. Since the contact body 73 in contact with the contact 30 has a hexagonal bolt shape, even if the contact body 73 needs to be replaced due to wear or the like, the contact body 73 can be easily replaced. A partial spherical contact surface 73 a is formed on the operation head of the contact body 73.

  As shown in FIGS. 10 and 12, the support 24 is provided with guide means 25 for slidably supporting the detector 26. The guide means 25 includes a guide block (guide body) 77 and a slide block 78 that is slidably supported by the guide block 77. The sliding direction of the slide block 78 and the axis of the sensor rod 28 are arranged in parallel. An L-shaped connecting body 79 is fastened and fixed to the front end side of the slide block 78 with a cap bolt. The sensor rod 28 is fixed by screwing a set bolt 81 in a state where the front end of the sensor rod 28 is inserted into the insertion hole 80 formed in the connecting body 79. Thus, the sensor rod 28 is supported in a cantilevered manner by the detector base 72, the connecting body 79, and the slide block 78 that connects both of them.

  As shown in FIGS. 10 and 12, the support 24 includes a support plate 83 and a mounting base 84, and is configured in an L shape by fastening and fixing both 83 and 84 with cap bolts. The previous guide block 77 is fastened and fixed to the mounting base 84 with a cap bolt. A fixing hole 85 for fixing the sensor head 29 is formed in the support plate 83 so as to penetrate in the front-rear direction. The head holder 86 is fixed to the fixing hole 85, and the sensor head 29 is located inside the head holder 86. Is fixed. The support plate 83 is formed with an insertion hole 87 that allows the slide block 78 to reciprocate. The detector base 72 and the connecting body 79 are fastened and fixed to the rear end and the front end of the slide block 78, respectively, and these three members are integrated. Stopper pins 88 are respectively fixed to the front and rear surfaces of the support plate 83, corresponding to the front and rear stopper pins 88, stopper bolts 89 are fixed to the detector base 72, and the stopper arms 90 are fixed to the coupling body 79. It is. Each stopper pin 88 abuts against the stopper bolt 89 or abuts against the stopper arm 90 to define the movement limit of the front and rear of the slide stroke of the detector 26.

  As shown in FIGS. 10 and 13, the return spring 92 is a compression coil type spring, and the return spring 92 is provided between the connecting body 79 and the front cover 93 provided on the front end side of the mounting base 84. The detector 26 is urged toward the standby position (rear end position). Thereby, the detector 26 is displaced in the front-rear direction so as to follow the contact 30. The guide block 77, the sensor head 29, and the like are protected by a cover 94. In the position detection device 2, the mounting base 84 is fastened and fixed to the frame-shaped mold 5 with cap bolts.

  In this embodiment, the damping mechanism 56 that restricts the displacement speed of the detector 26 is eliminated. This is because in the case of an injection molding machine in which the movable platen 16 is operated close to or away from the hydraulic cylinder 70, the moving speed of the movable platen 16 is low, and a bounce phenomenon occurs when the detector 26 and the contactor 30 come into contact with each other. Because it does not.

As described above, in the molding die position detecting apparatus according to the present embodiment, the guide block 25 and the slide block 78 constitute the guide means 25 that supports the detector 26 so that the detector 26 is slidable. The slide can be guided in a state of being firmly supported. Therefore, even when a large impact is applied to the detector 26 during mold clamping, the detector 26 can be prevented from being damaged, and the relative position between the fixed mold 3 and the movable mold 4 can be reliably detected. it can.
In addition, the detector 26 and the contact 30 are arranged on the movable mold 4 and the frame-shaped mold 5, respectively, so that both face each other. In a state where the relative position of the movable mold 4 is displaced with respect to the fixed mold 3, the detector 26 is directly displaced by the contact 30, and the displacement of the detector 26 is detected by the detection means 27, and the fixed mold 3 is detected. The relative position of the movable mold 4 was detected. According to such a position detection device, it is possible to eliminate an error that occurs when the sensor element is attached to the movable platen and the fixed platen, and the relative position between the fixed die 3 and the movable die 4 can be accurately determined. Can be detected. In addition, the detection value is not affected by the structure and material of the mold to be mounted, or the magnetic characteristics of the mold surface. Further, the detected value is not affected by the temperature unevenness of the surrounding air due to the heat of the mold.

  Since the detection means 27 is a high-resolution linear sensor composed of the sensor rod 28 and the sensor head 29, the relative position between the fixed mold 3 and the movable mold 4 can be accurately detected, and the molding mold 1 can improve the dimensional accuracy and shape accuracy of the product molded in step 1. Further, since the detector 26 is urged by the return spring 49 toward the standby position protruding from the support 24 toward the contact 30, the detector 26 can be brought into close contact with the contact 30 and can be followed. The relative position between the mold 3 and the movable mold 4 can be accurately detected.

  In the second embodiment, the mold clamping position detection sensor for detecting the mold clamping position is provided. However, this is not necessary, and the position detection device 2 is set by setting the output value of the linear sensor 27 at the mold clamping position in advance. It can be used as a mold clamping position detection sensor. The molding die 1 does not need to be constituted by the fixed die 3, the movable die 4, and the frame-like die 5. Even if the molding die 1 is constituted by two pieces, the fixed die 3 and the movable die 4. Good. In the second embodiment, the contact 30 and the detector 26 are in contact with each other with the molding die opened, but they may be disposed in a separated state.

DESCRIPTION OF SYMBOLS 1 Molding die 2 Position detection apparatus 3 Fixed mold 4 Movable mold 8 Clamping apparatus 24 Support body 25 Guide means 26 Detector 27 Detection means (linear sensor)
28 Sensor rod 29 Sensor head 30 Contact 37 Guide body (linear bush)
38 Slide body (Slide rod)
49 Return spring 54 Damper chamber 55 Liquid oil 56 Damping mechanism 59 Communication hole 63 Liquid holding body 64 Shape retaining member 65 Felt 77 Guide body (guide block)
78 Slide body (Slide block)
92 Return spring

Claims (8)

A molding die position detecting device for detecting a relative position between a fixed die and a movable die,
The position detecting device includes a support, a detector supported by the support so as to be slidable back and forth by guide means, a contact for operating the detector to be displaced during mold clamping, and the support provided on the support. Detecting means for detecting the position of the detector displaced by a contact;
The guide means includes a guide body fixed to the support body, and a slide body that is slidably supported by the guide body.
Either one of the support and the contact is disposed in any one of the molds constituting the molding die, and the other of the support and the contact is the support and the contact. Are arranged in a mold that moves relative to a mold in which either one of the detector and the contact are opposed to each other,
In a state where the relative position of the movable mold is displaced with respect to the fixed mold, the detector is directly displaced by the contact, and the displacement of the detector is detected by detection means, and the fixed mold and A molding die position detecting device for detecting a relative position with respect to the movable die. The detection means is composed of a linear sensor provided with a sensor rod that accompanies and moves with the detector, and a sensor head that is fixed to the support and detects the position of the sensor rod,
2. The molding die position detection device according to claim 1, wherein the detector is biased by a return spring toward a standby position protruding from the support toward the contact. A damping mechanism is provided between the support and the slide body to apply a damping force to the slide body when the detector is displaced,
The molding die position detection device according to claim 2, wherein the abrupt movement of the detector when the detector is displaced by the contact is regulated by the damping mechanism. The damping mechanism is composed of a damper chamber formed in the support body in a state surrounding the periphery of the slide body, and liquid oil and fat sealed in the damper chamber,
The molding die according to claim 3, wherein a sudden movement of the detector is regulated by a shearing force generated between the slide body and the liquid oil in a state where the detector is displaced by the contact. Position detector.   The molding die position detecting device according to claim 4, wherein a liquid holder impregnating the liquid oil is disposed in the damper chamber, and the liquid holder is externally fitted to the slide body.   6. The molding die position detecting device according to claim 5, wherein the liquid holding body is composed of a ring-shaped felt and a shape-retaining member that is attached to an outer surface of the felt to hold the felt shape. The support body is formed with a communication hole through which the liquid oil is taken in and out of the damper chamber, and the communication hole is closed with a detachable plug.
The molding die according to any one of claims 4 to 6, wherein the liquid oil or fat can be replenished in the damper chamber or the liquid oil or fat in the damper chamber can be replaced in a state where the stopper is removed from the support body. Position detector.   8. The molding die position detecting device according to claim 4, wherein the liquid oil is silicone oil.

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